XSPEC User's Guide

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40 add a component to our model. The editmod command lets us do this without having to respecify the model from scratch. Here, we'll add a black body component. XSPEC12>editmod pha(po+bb) Model: phabs[1]( powerlaw[2] + bbody[3] ) Input parameter value, delta, min, bot, top, and max values for ... Current: 3 0.01 0.0001 0.01 100 200 bbody:kT>2,0 Current: 1 0.01 0 0 1E+24 1E+24 bbody:norm>1.e-5 --------------------------------------------------------------------------- --------------------------------------------------------------------------- Model: phabs[1]( powerlaw[2] + bbody[3] ) Model Fit Model Component Parameter Unit Value par par comp 1 1 1 phabs nH 10^22 4.000 frozen 2 2 2 powerlaw PhoIndex 3.594 +/- 0.6867E-01 3 3 2 powerlaw norm 0.1161 +/- 0.9412E-02 4 4 3 bbody kT keV 2.000 frozen 5 5 3 bbody norm 1.0000E-05 +/- 0. --------------------------------------------------------------------------- --------------------------------------------------------------------------- Chi-Squared = 122.1538 using 31 PHA bins. Reduced chi-squared = 4.362635 for 28 degrees of freedom Null hypothesis probability = 9.963E-14 Notice that in specifying the initial values of the black body, we have frozen kT at 2 keV (the canonical temperature for nuclear burning on the surface of a neutron star in a low-mass X-ray binary) and started the normalization at zero. Without these measures, the fit might “lose its way”. Now, if we fit, we get (not showing all the iterations this time): --------------------------------------------------------------------------- Model: phabs[1]( powerlaw[2] + bbody[3] ) Model Fit Model Component Parameter Unit Value par par comp 1 1 1 phabs nH 10^22 4.000 frozen 2 2 2 powerlaw PhoIndex 4.932 +/- 0.1618 3 3 2 powerlaw norm 0.3761 +/- 0.5449E-01 4 4 3 bbody kT keV 2.000 frozen 5 5 3 bbody norm 2.3212E-04 +/- 0.3966E-04 --------------------------------------------------------------------------- --------------------------------------------------------------------------- Chi-Squared = 55.63374 using 31 PHA bins. Reduced chi-squared = 1.986919 for 28 degrees of freedom Null hypothesis probability = 1.425E-03 The fit is better than the one with just a power law and the fixed Galactic column, but it is still not good. Thawing the black body temperature and fitting gives us:
41 XSPEC12>thaw 4 Number of variable fit parameters = 4 XSPEC12>fit ... --------------------------------------------------------------------------- --------------------------------------------------------------------------- Model: phabs[1]( powerlaw[2] + bbody[3] ) Model Fit Model Component Parameter Unit Value par par comp 1 1 1 phabs nH 10^22 4.000 frozen 2 2 2 powerlaw PhoIndex 6.401 +/- 0.3873 3 3 2 powerlaw norm 1.086 +/- 0.3032 4 4 3 bbody kT keV 1.199 +/- 0.8082E-01 5 5 3 bbody norm 2.6530E-04 +/- 0.3371E-04 --------------------------------------------------------------------------- --------------------------------------------------------------------------- Chi-Squared = 37.21207 using 31 PHA bins. Reduced chi-squared = 1.378225 for 27 degrees of freedom Null hypothesis probability = 9.118E-02 Figure F: The result of the command plot model in the case of the ME data file from 1E1048.1— 5937. Here, the model is the best-fitting combination of power law, black body and fixed Galactic absorption. The three lines show the two continuum components (absorbed to the same degree) and their sum.
Page 1 and 2: An X-Ray Spectral Fitting Package U
Page 3 and 4: iii 3.9.1 What to do when you have
Page 5 and 6: v 5.7.3 iplot: make a plot, and lea
Page 7 and 8: vii 6.2.67 step: step function conv
Page 9 and 10: Updates to the manual July 2009 (v1
Page 11 and 12: 1 1. XSPEC XSPEC is a command-drive
Page 13 and 14: 3 1.2 How to find out more informat
Page 15 and 16: 5 2. Spectral Fitting and XSPEC 2.1
Page 17 and 18: 7 These components are used i
Page 19 and 20: 9 may be ignored. This can be chang
Page 21 and 22: 11 • Auxiliary Responses: callib/
Page 23 and 24: 13 Bevington, P.R., 2002, 3 rd Edit
Page 25 and 26: 15 Model commands define and manipu
Page 27 and 28: 17 3.7 Data Commands XSPEC is desig
Page 29 and 30: 19 3.8.1 Models with multiple respo
Page 31 and 32: 21 additive model components on dat
Page 33 and 34: 23 #LOCAL_MODEL_DIRECTORY: /path/to
Page 35 and 36: 25 # USE_NUMERICAL_DIFFERENTIATION:
Page 37 and 38: 27 %xspec XSPEC12>data s54405.pha 1
Page 39 and 40: 29 cutoffpl disk diskbb diskline di
Page 41 and 42: 31 Figure B: The result of the comm
Page 43 and 44: 33 Figure C: The result of the comm
Page 45 and 46: 35 such as iron emission lines and
Page 47 and 48: 37 XSPEC12>mo pha(br) Model: phabs[
Page 49: 39 XSPEC12>fit ... ----------------
Page 53 and 54: 43 Null hypothesis probability = 0.
Page 55 and 56: 45 mission; however, it has now bee
Page 57 and 58: 47 1 1 1 phabs nH 10^22 0.2574 +/-
Page 59 and 60: 49 Here, the first group makes up t
Page 61 and 62: 51 --------------------------------
Page 63 and 64: 53 using response (RMF) file... s0c
Page 65 and 66: 55 The first thing we'll do is chan
Page 67 and 68: 57 selecting the "PHA" output optio
Page 69 and 70: 59 ________________________________
Page 71 and 72: 61 effects of the coded-mask. The l
Page 73 and 74: 63 particular background model empl
Page 75 and 76: 65 One might then make a second pas
Page 77 and 78: 67 5. XSPEC commands 5.1 Summary of
Page 79 and 80: 69 Command Category Description goo
Page 81 and 82: 71 Command Category Description rth
Page 83 and 84: 73 //This setting essentially disab
Page 85 and 86: 75 If no is given, then the file s
Page 87 and 88: 77 XSPEC12> show rparameters // All
Page 89 and 90: 79 8. search failed in +ve directio
Page 91 and 92: 81 solab stat statmethod steppar st
Page 93 and 94: 83 5.4 Data Commands 5.4.1 arf: cha
Page 95 and 96: 85 is equivalent to no correction f
Page 97 and 98: 87 For files with multiple spectra
Page 99 and 100: 89 which assumes that at least two
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91 number of fakeit spectra produce
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93 confusion can arise when the row
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95 If integers are given for the ch
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97 =:: [[:]] ..., and is the name
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99 Either format is readable when u
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101 For high-chatter settings, addi
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103 XSPEC12>chain temperature .8 //
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105 5.5.5 freeze: set parameters as
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107 margin (for 1-D and 2-D distrib
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109 where =:: [sourceNum:] | -- T
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111 where n is the component number
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113 is range of positions in the m
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115 Detector channel energies 5.0 -
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117 Similarly, an array extension c
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119 the energy values are two separ
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121 XSPEC commands for editing/view
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123 // Spectrum 3 response will ret
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125 Syntax: lmod [directory] As fo
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127 5.6.14 mdefine: Define a simple
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129 ***Warning: bb is a pre-defined
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131 makes the model named active (
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133 Applying multiple models: Assum
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135 (XSPEC will reject attempts to
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137 5.7 Plot Commands 5.7.1 cpd: se
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139 This command works like the plo
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141 eemodel Plot the current incide
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143 area, noarea After setplot area
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145 /KRM3 /TK4100 /VT125DEC /XDISP
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147 poiss-3 is the arithmetic mean
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149 Mg 3.80e-05 3.80e-05 3.95e-05 3
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151 XSPEC12.0 includes version94.1
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XSPEC Models 153 5.8.6 xset: set va
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XSPEC Models 155 WMAP. SUZPSF-MIXFA
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XSPEC Models 157 5.9 Tcl Scripts Th
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XSPEC Models 159 5.9.5 writefits: w
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XSPEC Models 161 6. XSPEC V12 Model
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XSPEC Models 163 Model Description
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XSPEC Models 165 Model Description
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XSPEC Models 167 Thermal broadening
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XSPEC Models 169 The bapec model us
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XSPEC Models 171 The zbbody variant
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XSPEC Models 173 par4 E c , the e-f
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XSPEC Models 175 par2 par3 Energy s
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XSPEC Models 177 hydrogen density (
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XSPEC Models 179 par2 par3 par4 par
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XSPEC Models 181 The region of para
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XSPEC Models 183 6.2.19 compTT: Com
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XSPEC Models 185 6.2.23 Diskir: Irr
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XSPEC Models 187 6.2.27 diskpbb: ac
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XSPEC Models 189 Borkowski, Lyerly
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XSPEC Models 191 The vgnei variant
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XSPEC Models 193 par2 second powe
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XSPEC Models 195 6.2.38 kerrdisk: a
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XSPEC Models 197 elements. Abundanc
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XSPEC Models 199 par1 plasma temper
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XSPEC Models 201 6.2.45 nei, vnei:
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XSPEC Models 203 par4 Lower limit o
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XSPEC Models 205 6.2.48 nsagrav: NS
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XSPEC Models 207 par1 par2 par3 A =
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XSPEC Models 209 6.2.53 pegpwrlw: p
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XSPEC Models 211 6.2.56 plcabs: pow
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XSPEC Models 213 6.2.59 pshock, vps
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XSPEC Models 215 par1 par2-par13 pa
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XSPEC Models 217 1.1 but uses APED
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XSPEC Models 221 6.2.66 sresc: sync
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XSPEC Models 223 par6 par7 Number o
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XSPEC Models 225 XSPEC12>model etab
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XSPEC Models 227 source frame. Futu
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XSPEC Models 229 par1= n H equivale
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XSPEC Models 231 par1= E c par2= f
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XSPEC Models 233 6.3.26 tbabs, ztba
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XSPEC Models 235 The zvarabs varian
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XSPEC Models 237 varies between 1 a
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XSPEC Models 239 energy ranges of t
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XSPEC Models 241 par2= max Maximum
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XSPEC Models 243 where: par1= par2
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XSPEC Models 247 If multiple observ
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XSPEC Models 249 6.6.5 xmmpsf: xmm
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A-251 Appendix A Appendices The Use
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A-253 120 XSPEC12> This would produ
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A-255 After being executed, many tc
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A-257 in order to start a C-shell.
Page 269 and 270:
A-259 Note that the model string, w
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A-261 Appendix B Fitting with few c
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A-263 1 C y0( x ) i y0( xi) y0(
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A-265 Appendix C Adding models to X
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A-267 first should be set to 1 if m
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A-269 const string& init Initializa
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Appendix D Overview of PLT A-271 As
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A-273 Freeze GAp Grid Hardcopy HElp
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A-275
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A-277 The directory ftools/callib/s
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A-279 csmgh0 Get the cosmology H0 s
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Appendix G Adding a Custom Chain Pr
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A-283 model parameter values. The o
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A-285 (and can be ignored if not re
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A-287 Additionally, we have withdra
Page 299:
A-289 There are minor plotting
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